Breast cancer (BCa) survival rates among older African-American (AA) women continue to lag behind that of older Non-Hispanic Whites (NHW). In addition, the association between low socioeconomic status (SES) and increased BCa mortality has been found to be more apparent among older racial/ethnic minorities including AA. The poor health status of older AA women at the time of BCa diagnosis has been hypothesized to blunt the long-term benefit from cancer treatment, leading to racial disparities in BCa survival Functional status, the ability to perform Basic and Instrumental Activities of Daily Living, is a ky summary measure of health status. Older AA and SES-disadvantaged BCa survivors are disproportionately affected by functional disability. Therefore, we hypothesize that a targeted intervention to address functional disability during the early BCa survivorship period will reduce racial and SES-related disparities in functional disability and may in the long- term, improve the functional and health status of older AA and SES-disadvantaged BCa survivors, optimizing their long-term benefits from breast cancer treatment. However, PA intervention studies that focus on older AA and SES-disadvantaged BCa survivors, two groups that are particularly at risk for functional disability, are lacking. To develop a physical activity intervention that is feasible, acceptable and sustainable among older African-American and SES- disadvantaged breast cancer survivors requires that the intervention be informed by the social and cultural context that surround such women. Therefore, we will first conduct interviews among 45 African-American and/or SES-disadvantaged breast cancer survivors to explore beliefs, attitudes and preferences of women towards physical activity. We will then use the information distilled to develop a culturally-sensitive physical activity intervention. The culturally-sensitive physical activity intervention will then be tested in a randomized- controlled clinical trial of 236 African-American and/or SES-disadvantaged breast cancer survivors, aged = 65 years. Our specific aims are: 1) To assess physical activity attitudes, beliefs and preferences of older AA and older SES-disadvantaged BCa survivors to inform the development of a PA intervention that will foster initial enrollment and sustained participation; 2) To determine the effect of the refined and culturally-sensitive PA intervention on functional outcomes (physical performance and functional disability) at 20 and 52 weeks; and 3) To evaluate how PA attitudes, beliefs and preferences of older AA and/or SES-disadvantaged stage I-III BCa survivors moderate differences in PA levels and functional outcomes. This study is innovative because it includes two disparities and underserved populations, (older AA BCa survivors and SES-disadvantaged BCa survivors) in one study. The study is significant because a feasible, effective and sustainable PA intervention for older AA and SES-disadvantaged BCa survivors, groups that are disproportionately affected by poor functional and health outcomes, may reduce racial disparities in functional and health outcomes, translating to improved breast cancer outcomes in the long-term.